Power tools are known that have a battery pack, which serves as a power supply, mounted to a tool main body (e.g., refer to the page on which the BL1430 appears in the Makita General Catalog published April 2012). Such a power tool battery pack comprises a rechargeable battery that can be attached to and detached from the tool main body. That is, after the power tool battery pack is attached to the tool main body and used, the power tool battery pack is detached from the tool main body and charged by a specialized charger. After charging, the power tool battery pack is once again attached to the tool main body. As used herein, tool main bodies, specialized chargers, and other structures to which a power tool battery pack may be mounted are sometimes referred to as “mounting targets.”
Power tool battery packs generally comprise a case (housing), which also functions as an outer packaging (shell), and a battery main body that is installed inside the case. The battery main body comprises a plurality of rechargeable battery cells and a circuit board that controls the charging and discharging of the plurality of battery cells. The circuit board includes positive and negative connection terminals through which electric current passes when the battery cells are charged and discharged. In addition, the circuit board is provided with signal terminals for transmitting signals to and receiving signals from outside the battery pack—from a mounting target such as the attached tool main body, the attached charger, etc.
When the power tool battery pack is mounted onto a mounting target, the signal terminals constitute communication signal terminals that transmit information to and receive information from the power tool battery pack. A separate signal terminal is generally provided for different types of information. Consequently, a plurality of the signal terminals is generally provided, and these signal terminals are disposed adjacently.